‘Laser comb’ could help find alien planets

A new tool could aid planet hunters in the search for Earth-like alien planets.

Scientists published a study in the May 31 edition of the journal Nature in which they detail results from testing their laser frequency comb–a calibration tool for large ground-based planet-hunting telescopes. Some of these telescopes locate planets by observing the gravitational effect, or wobble, these potential planets have on their parent stars. Current tools are reportedly limited in function, and lack precision. For example, the European Southern Observatory’s High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph on a telescope at the La Silla Observatory in Chile searches for planets using this “wobble method.”

The La Silla Observatory in Chile. (Credit: ESO)

But according to Space.com, “precision is key, and the hollow cathode lamps used to calibrate those spectrometers have their limitations . . . they are not adjustable, can be difficult to gauge, and allow the spectrometers to track the wobble of a star only down to about 30 centimeters per second.” And, as study co-author Gaspare Lo Curto of the European Southern Observatory explains, the detection of Earth-sized planets requires that precision, multiplied by ten.

Lo Curto and his colleagues tested the laser frequency comb on the HARPS. The researchers claim this tool provides the required accuracy enhancement. Space.com explains that the laser frequency comb works by emitting “many lines of light spread apart like the teeth of a comb.” And because the distance between these “teeth” is known, it is possible to more accurately gauge “wobble.”

Although the laser comb is capable of detecting planets with masses similar to Earth, the limitations of the telescopes themselves currently prevent this. Researchers say that the HARPS, even with a laser comb, would not be capable of detecting planets less massive than Neptune-size planets in the habitable zone around sun-like stars. For reference, Neptune’s mass is seventeen times that of Earth. But optimistic researchers contend that larger telescopes currently being constructed, when fit with a laser comb, will be able to detect Earth-mass planet in the habitable zone of a sun-like star.

About Jason McClellan

Jason McClellan is a UFO journalist and the producer/co-host of the web series Spacing Out! He is also the web content manager and staff writer for OpenMinds.tv, and a co-organizer and technical producer of the International UFO Congress. As a founding member of Open Minds, Jason served as a writer and editor for the now defunct Open Minds magazine. He has appeared on Syfy, NatGeo, and, most recently, he co-starred on H2's Hangar 1: The UFO Files.
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